I am trying to get my air conditioner to go back on. Our Magic Stat(Honeywell) model # CT3300A1009 9224. I had a display on the thermo that said low battery, so I replaced them & now I can't get anything to display on the thermo. The fan works, but the air does not kick on & the face plate says nothing.

All Honeywell t-stats have a model # and a 1-800 #. Call them! Have your t-stat apart to see the model#. Or if you don't know how to take it apart call them first. Ask Mr. Google for Honeywell customer service #. Their customer service is usually %100 in helping me when needed.

Depends on what t-stat you have. Need a make of tstat and model # or style.

this control has an option for back light display in the set up menu. if it has never worked this may be the problem. if it did work then quit you should replace the t-stat. there are many different models as they have advanced over the years. this is a great control. see if you can find the set up manual

I believe you have a thermostat for a different application. All home thermostats have R,W,Y,G and sometimes also O,B. Good luck hope this helps.

the wall stat maybe bad. or wires to remote stat may be shorted

Remove main stat from subbase. On back of main stat there are some screws used for different settings. Screw "C" if for fahrenheit and celcius. Screw in for fahrenheit and out 1 turn for celcius.

Hi,
Do not know what model t-stat you have and they are different depending on what t=stat you have...

Go here and down load the manul for you t-stat which will then tell you how you can unlock it...

Manual Honeywell How to Find Honeywell Manuals
http://www.fixya.com/support/r3894275-manual_honeywell_find_honeywell_manuals

heatman101

Hello,You forgot to wire the O terminal w1 witch is the reversing valve.It is important to check if old stat is using O or B in witch case B terminal=w1 leaving O unused.

That is a NONprogramable T-stat. There is no program to overide, therefore there is no need for a "hold" option. To set the temp, place the switch on the side marked

COOL
OFF
HEAT

to the desired setting, and push the up down arrows on the front until the display shows 80.

The DISPLAY will revert back to the current room temperature within a few seconds, and will keep the unit on until it reaches the desired temp.

The set temperature remains at 80, it just shows the current room temp.

Sounds to me like you have a low voltage short. If the stat had no display until you installed the battery means there was no voltage for the stat to work. Putting the battery in proves the stat works, no motors turning on probably leads to a blown low voltage fuse generally a blade fuse on circuit board in indoor unit. Good Luck